Conventional materials for use as wound dressings, such as cotton gauze, suffer from a number of disadvantages. For example, cotton gauze tends to stick to the wound during the healing process. Removal of the wound dressing under these circumstances destroys tissue and is uncomfortable for the patient. To reduce sticking and optimize wound healing, the wound dressing must be replaced often.
Another disadvantage of using cotton gauze in wound dressings arises from the construction of the gauze material. Cotton gauze is manufactured from twisted cotton fiber which is cleaned, bleached and sterilized. During the cleaning and bleaching process, the thread is exposed to chemical treatments and becomes associated with leftover starch, proteins, casein and resins. These materials, plus small fibers or lint, often disassociate from the cotton gauze and contaminate the wound. In some cases, particularly during surgery, serious infections can result.
Efforts have been made to overcome the disadvantages associated with gauze-type wound dressings by coating or impregnating the gauze material. Romano Cali, U.S. Pat. No. 4,748,976 discloses a wound dressing in which a cotton fabric is impregnated with a cosmetic preparation held in an oil or a grease medium. Nigel J. Brassington et al., U.S. Pat. No. 4,838,253 disclose a wound dressing comprised of a cotton gauze coated with a tacky silicone gel or a non-tacky silicone elastomer.
Paul F. Hermann et al., U.S. Pat. No. 5,135,472 disclose a composite gauze material coated with a hydrophilic polymer. The polymer is stated to bind with the hydroxyl groups of the gauze material. Such polymers include a polyurethane foam prepolymer, and polymers of ethylene oxide, carboxymethyl cellulose or polyvinylpyrrolidone.
Despite these efforts there is a continuing need to develop composite materials for use as wound dressings which are highly absorbent, do not stick to the wound and reduce or eliminate infiltration of fibers and by-products of manufacture into the wound.